Tack pulling machine



July 2, 1940.. R. :..GRif-'Fm Erm..

TACK rULLgNG ummm Filed July 1. 193s s sheets-sheet 1 R. L. GRIFFIN ET AL TACK PULLING MACHINE 3 Sheets-Sheet 2 Filed July l, 1938 NNN July 2, 1940.

R. L. GRIFFIN-I'AL.

TACK PULLING MACHINE Filed July 1, 1958 3 Sheets-Sheet 3 Ww. 2 Q

Patented July 2, 1940 UNITED NSTATES 2,206,253 TACK PULLINGMACHINE Roger L. Griiitin, Marblehead, and Norman Y. l\/Ioore,` Danvers, Mass., assignors to A. C. Lawrence Leather Company, `Peabody, Mass., a corporation of MaineV i 'i Application July 1, 193s, serial No. eimer 29 Claims. (Cl. 2519-18)` The present invention relatesto tack pulling` machines, and more particularly toa machine designed primarily for removing tacks from boards `upon which hides or skins have been stretched and dried.

In practice, the tanned skins while still Wet are stretched out and tacked to the Wooden "stretching frames or "boards as they are called, which `are then passed through drying chambers after which the tacks are withdrawn and the dry skins removed from the boards.

. It is the object of the present invention `to provide a novel and improved tack pulling machine for automatically removing thetacksifrom a plurality of boards presented successively to the machine by a conveyor system.

Another object of the invention is to provide attack pulling machine having light weight and u resilient tack engaging members, which not only will yield in the event of misengagement `oi said membersfwith the heads of the tacks and thus avoid bending` the tacks or driving them further into the board, but which, because of such resiliency of the members, will also propel or throw `the tack clear of the board and leather and into a. collector." i

A further object is to provide a tack pulling machine having improved hold-down mechanism for preventing the skin from being lifted into Contact with Vthe tack pulling elements as the tacks are Withdrawn, or any portion of the skin which may have been detached from the board during the drying operation from becoming entangled with the tack-pulling device, thus preventing injury to the leather and damage to the tack-pulling device.

` Another object is to providea simple and inexpensive construction of tack-pulling tool having tack engaging elements in the form of tensioned wireswherein the tension on the wires may be i easily adjusted or varied as desired while automatically maintaining an equal tension on each. Also, wherein the Wires `may be removed and replaced With a minimum expenditure of effort and Also, a traveling hold-down mechanism which i. `moves with the` board and skins and holds the lrotary tack-pulling tool which is provided with skin down firmly on the `boards as they pass ybeneath the tack-pulling tool. Also, a conveyor or other means for feeding the boards beneath the tack-pulling tool and a hood or `other suitable collecting device for catching the tacks as they are thrown oir by the resilient tackpulling members, together with delivery means for discharging the collected tacks at some convenient point outside the` machine. v

In the drawings illustrating the preferred embodimentof` the invention, Fig. l is a View in front elevation, partly in section, of thecomplete machine, `a.pcrtion of the enclosing casing and of the hold-down mechanism being omitted for purpose of `lclearness of illustration; Fig. 2 is a sectional .view in side elevation taken along `the line 2 2 of Fig. 1; Fig. 3 is a longitudinal sectional View, on a` larger scalepof a portion of the tack-pulling tool and hold-down mechanism, and showing` a board and skin positioned` `beneath said tool; Fig. 4 is a transversesectional f vievv of the parts illustrated in Fig. 3 taken along the line 4 4 of said gure; and Fig. 5 is an end View of the tack-pulling tool with the tackpulling members or wiresom-itted, the view being taken along the line 5-5 of Fig. 3.

Briey, the machine illustrated in the drawings comprises a conveyor for feeding the boards with the dried leather tacked thereto past a a cylindrically arrangedseries of longitudinally i' extending, tightly stretched wires to engage the under side of the` heads of the tacks and rst `Withdraw them and then throw them forcibly into an adjacent collector o-r hood. A continuously moving transverse belt or conveyor beneath the hood receives the tacks therefrom and carries them Voutside the machine where they fall into a receptacle The hold-down mechanism comprises a series of spaced transverse rods or bars carried, at `their ends on endless chains, continuously driven in the same direction and at the same speed as Ago `the boards themselves, and arranged to be brought down between the tacks to engage and hold the skin from rising as it passes beneath the tackpulling tool. p

The feeding mechanism which carries the boards 'l andattached hides 9 beneath and past the tack-pulling tool comprises carriages Il supported by the flanged wheels I3 on opposite ends of the shafts I4 mounted on and extending across the carriage. The Wheels I3 run upon rails I5 secured upon the transverse members I1 of the machine frame. AUponeach carriage Il is posispondingly upstanding flanges 3| having driving. if

notches 33.

The conveyor carriages are moved along the tracks by endless chains 35, one on each side of the machine, attached' to each carriage by bearing pieces 35 which t over the ends of the carriage shafts I4. The chains run within channel member 31 mounted vori-the opposite ends of the transverse frame member l1, and are driven in conventional fashion by a source of power, not

shown. In order to provide support for the conveyor chain 35 between the flanged wheels |,3 the rails 38 are provided (see Fig. 1), mounted on transverse members I1 of the machine frame. Preferably, in order that theboards may be positioned accurately beneath the tack-pulling mechanism and not be affected by` variations in the carriages, supplementary guiding rolls may be provided adjacent the tack-pulling tool for the platform. Thus idler rolls 39 mounted on the sides of the machine frame serve to align the platform with respect to vertical position, these rolls bearing on the under side 0f the platform, while horizontal alignment is insured by idler rolls 4|, 43, which bear against the anged end members of the boards themselves.v The pivots of idler rol1s 4| on the left hand side of the machine, as Vviewed in'Fig. 1, are springpressed inwardly so that the board will always bear against rolls 43 mounted in xed position on the opposite side of the machine, thus eliminating any possibility of the board canting and becoming jammed cornerwise. Stop screws. 45 limit the amount the idler rolls 4|,may move inwardly when no board is in engagement therewith.

The tacks are pulled from the boards by means cfa rotating tool or reel (see Figs. 3, 4 and 5), y

which rotates in acounterclockwise direction, as viewed in Fig. 2, so that the bottom or operative portion of the tool moves oppositely to the boards as they pass through the machine on the conveyor. The tack-engaging elements of the reel consist of wires or thin rods 41 arranged parallel vabout the reel shaft 49 as elements of a cylinder. A satisfactory arrangement consists of three of these wires spaced at 120 apart in the reel. The wires are stretched under tension between the reel ends or heads 59 and 5| 'having short radial slots 53 directed outwardly toward the periphery into which slots the wires slide in assembling the reel. The ends of the wires have secured thereto small conically-shaped buttons or beads 54, the wire beyond the beads being headed over to retain the beads. In assembling, these beads are passed through the openings 52 in the heads and then seated in Reel head 50 is of integral construction with .its hub Xed to the shaft 49 by a set screw or other suitable means, while the head 5| is so constructed as to be capable of axial movement to tion of the parts.

mounted on the shaft and provided with the circular openings 52 adjust the tension of the wires and to permit replacement of the same. Provision is also made for slight angular movement of the head, or a portion thereof, to equalize the tension of the several tack-pulling wires. The construction of the adjustable end 5| is illustrated in Figs. 3 and 5 and comprises a sleeve 56 secured to the reel shaft by the set screw 51. One end of the sleeve is externally threaded as at 59, and a key way 6| is also provided. The end plate or disc 63 which supports the wires is loosely mounted on the sleeve 56 so as to permit free axial and substantial angular movement thereon, a key 65 secured to said end plate by screw 61 and fitting loosely in the key way 6| preventing relative rota- The end plate B3 is moved outwardly along the sleeve by means of an internally threaded collar 69 which engages the threaded portion 59 of the sleeve. The collar is provided with recesses 1| about its circumference to receive a suitable tool or wrench for rotating the same.

As shown in Fig. 3, the mutually engaging faces on the disc 63 and threaded collar 69 are spherically concave and convex, respectively, as invariations inthe lengths of wires between their upset ends. f

, The wires 41 during the tack-pulling operation are deflected from their normal position by the resistance of the tack to withdrawal, so that when the tack does pull out, the wire snaps back and vibrates with substantial amplitude. Such vibration tends to weaken the wires adjacent the supporting ends or heads, so that breakage may result. To dampen this oscillation or vibration, supplementary discs 13, illustrated in Figs. 3 and 4, are mounted on the reel shaft intermediate and adjacent the reelheads 59 and 5|. The supplementary discs are secured to the reel shaft 49 by means of set screws 15 and have radial slots 11 extending axially through the outer portion of the discs, The radial inner end of each slot is enlarged at 19 to permit the passage therethrough of the heads 54 on the ends of the wires, in assembling the reel.v Preferably the radius of the outer end of the slots 11 is slightly greater than the radius of the outer end of the slots 53 in the ends or heads 59 and 5|,`

so that the wires will necessarily extend in a straight line from one end of the reel to the injury. In .order to keep the hides iiat on the boards during their passage through the Inachine, hold-down mechanism is provided analogous to an inverted conveyor system, having thin crossbars which rest on the hide between the tacks and move along with the boards at the same rate of speed.

This hold-down mechanism comprises endless side chains 8| (see Fig. 2), running over large sprocket wheels 83 secured to transverse shafts and 81. These shafts are journalled in bearings 98 secured to the sliding plates 89 normally xedly mounted on the sides of the machine y no 'I0 i leather or otherwise, so that they contact the I frame, but arranged for up and down adjustment, the frame being provided with vertical slots through which extend the ends of the shaft means of a two-part connection, as shown -in Fig. 3. This comprises an outer sleeve 95hav.- ing an opening in the end of less diameter than the bore of the sleeve. In assembling, the reduced end 94 of the rod 93 is passed through this opening and `then `upset or headed over, thus securing the outer sleeve to the end of the rod, but with capacity for limited relative longitudinal movement. Pinned within the sleeve at its open end is the innermember 96 having an extension` 91 of reduced diameter which serves `as the pivotpin of the chain. Conveniently, the parts` 96 are assembled firstgwith the chain 8|, thus permitting the positioning of the chains on the sprockets and the later attachment of the rods 93.

i tacks by the wires of the reel.

'Ihe rods are sufiiciently flexible so that they will adapt themselves to the varying arrangement of the tacks, slipping down between adjacent heads and thus` permitting the engagement of all In order to avoid the possibility of tacks or the leather being jammed as'they pass beneath the shafts 85 and 91, these are adjusted vertically so that normally there would be about one and a half inches clearance between `the rods directly under the shafts and the boards on which the leather is tacked, suicient slackness being provided in the cha-ins 9|, however, to permit the rods to rest upon the leather throughout sub- `stantially the entire length of the lower horizontal leg of the chains.

The slackness thus provided, supplementedby the cumulative looseness `of the chain pivots, permits forward and backalong the board contacting portion.

i The hold-down chains 8| are driven by the sprocket 83 on the shaft 'Lwhich in turn is driven from the return leg 99 of one of the conveyor chains by means of the sprocket ||IIJ on horizontal shaft 60|, bevel gears |02, vertical shaft |93 and `gears |04, the` ratios being such that the linear speed ofthe hold-down rods is exactly the same as that of the boards carrying `the leather, so that the rods after they are brought into contact with the leather have no movement relatively thereto until they move out of contact after `the tack-pulling operationis completed. Preferably, the shaft |03 is formed in two sections connected by means of a sleeve and shear pin to protect the mechanism from injury in theievent that the hold-down bars or other actuating mechanism become jammed for any reason. To prevent the rods 93 from being raised by curved edges of the rapidly rotating peripheries of the heads and 5| of the tack-pulling tool and are ldamaged thereby, two rolls or discs |95 have been provided, one at each end of the rotating tool, freely ro-` i tatable on ball bearings |06 on the shaft `|9 immediately above and slightly spaced from` the sprocket chain 8|. These discs are of slightly larger" diameter than the heads of the tack-pulling reel, but will prevent upward movement sufficientto bring the rods into damaging contact with the heads `of the reel.

The sprockets and chains of the hold-down mechanism arefenclosed between the sides |01 and top 108, the end portions |09 of the latter being hinged at IIII to permit their being raised to give access to the sprocket wheels, chains, and bars at'each end of the machine. These end portions terminate well above the path of movement of the boards through the machine to pro- 4ing an operator or lodging in the operative parts of the machine, but also for gathering and removing them from the machine at afpredeter- `mined point in a continuous operation. i

The collector or -hood III, best shown in Fig. 2, extends entirely across the machine between the sides |91 and serves as a barrier or stop for the tacks. A curtain or rebound trap I2, comprising a plurality of strings or wires hanging from the peak of the hood, prevents the tacks from bouncing out of the hood after striking the same, stopping the tacks either asthey are thrown off from the tack-pulling reel or on the rebound from the back of the hood after they have penetrated the curtain. In order to avoid the possibility of re from sparks caused by the impact of the tacks on the hood or other parts, the curtain, when formed of string or other combustible material, will be chemically treated to render it reproof.

The bottom of the hood is formed with a wide shallow channel I3 in which runs an endless conveyor belt IM, upon which the tacks fall after they are thrown against or through the curtain. This belt runs through openings in the sides of the machine and over upper pulleys ||5 and ||6 at each end of the channel beneath the conveyor track, and over lower pulleys ||1 rotatably mounted between vertical members ||9 comprising .part of `the frame of the machine. The pivot shaft of upper pulley I I6 is arranged for adjustment by means of threaded studs I 2| to obtain correct tension of the belt, while pulley ||5 is mounted in iixed pivots and is rotated at a slow rate to drive the,` conveyor belt by mechanism hereinafter described.

`The tacks are discharged `from the belt as it passes over the pulley, falling into a suitable container. I

The tack pulling reel is rotated at moderately high speed, of the order of several hundred revolutions per minute, by means of a motor `|23 which drives the reel through a conventional V- belt |25 runing `over motor pulley |21 and pulley ,|29 on the reelshaft. At the other end of the reel' shaft is a small pulley ,|3|, which drives pulley |33 of a speed reducing mechanism |35 by belt |31. 'Ihedriving pulley for the tack conveying belt is driven from'thelow speed shaft of ythe speed reducer by a chain |39 running over sprockets IM and |43. The reduction in speed between the reel shaft and the belt driving pulley should be such as to provide a conveyor belt speed of vthe vorder of a few feet per minute.

Inioperation the feed or'conveyor mechanism for the boards is driven continuously and at a slow rate. The boards with the dried skinstacked thereto are presented to the conveyor at some distant point by hand or machine in yany suitable manner, andare positioned on the platform of the carriages with the driving brackets'or projections of the platform entering the driving recesses in the boards.

As the carriages carrying the boards approach the tack pulling tool, the carriages ride up on the supporting vrollers to bring the boards at proper height for the-tack pulling operation, and at the same time the side guide rolls hold the boards from angular displacement.

Meanwhile the boards with their tacked skins have come beneath the rst sprocket and the hold down bars have been 'brought downwardly into contactwith the board and skin, passing between the tacks and shifting bodily or flexing to one side or the other of the tacks which they strike in their descent. The boards reach the rotating tack pulling reel with the skinsheld firmly between the boards and the hold down bars, with the tacks standing substantially upright with their heads well above the bars. The tack pulling wires which are moving rearwardly just above the hold down bars engage beneath the heads of the advancing tacks and pull them out, throwing Athem into the hood where they fall onto the belt conveyor by which lthey are carried to a point outside o-f the machine and discharged intol a receptacle.

After the tacks are withdrawn the board and skin continue to be fed along with the skin tightly clamped against the board by the hold fdown bars. Not until the skin is well pastl the tack pulling reel and out ofany possible contact therewith are the bars raised andthe skin freed.

Due to the resilient character 0f the tack pulling members, i. e., the wres,.there is more or less yielding engagement of the latter with the tacks, thus greatly reducing, if not eliminating entirely the possibility of aA bending over of the tacks without pulling them, as may and does occur where a rigid, unyieldingtack engaging` tool is employed.v l 1 Furthermore, the resiliency o-f the tool throws the withdrawn tacks with such force and accuracy that they may be collected at some convenient point a substantial distance from the tool.

While the invention has been illustrated and described as embodied in connection with a machine for pulling tacks from boards and skins carried thereby, it is not necessarily limited to such a use, but may be employed in other machines and for other `uses within the scope of the appended claims. Nor is the invention limited to the specific forms and constructions herein shown and described, but/ these may be varied and altered as desired within'the language of the claims.

lThe nature and scope of the invention having been thus described, what is claimed is:

l. A tack pulling machine having, in combination, a rotating tack pulling tool, means for supporting the work as it is fed past the tool, and a hold-down. mechanism traveling with the work vto hold the latter when the tacks are withdrawn by the tool.

2. A tack pulling machine having, in combination, a rotating tack pulling tool, means for feeding` the work beneath and past thetack pulling toollin avdirection opposite to the movement of the tack engaging portion of the tool, and devices engaging the work in advance of the tool and movable with the work past the tool to hold the work against the action of the tool. I 3.'A tack pulling machine having, in combination,`a'rotating taclcpulling tool, feeding mechanismfor feeding theworkpast the tool comprising conveyor chains, carriages connected to the chains, supplementary platforms on the carriages for vsupporting the work, and means independent offthe carriage for supporting the platforms while guiding the same past the tack pullingtool. Y

4. A tack pulling machine having, in combination, `a rotating Itack pulling tool, feeding mechanism for. feeding thefwork-supporting boards past the tool and comprising conveyor chains, carriages connected to the chains, and supplementary platformso'n the carriages for supporting the boards, "and guiding mechanism for guiding the work past'the tool comprising rolls for engaging'the platform to position the same vertically with respect to the' tack pulling tool, and edgeguide rolls for engaging the edges of the board to position the same horizontally with respect to the tack pulling tool.

5. A tack pulling machine having, in combination, a rotating'tack pulling tool, work-supporting boards to,v which the work'is tacked, provided with metallic yedge members having notched flanges, feeding mechanism for feeding the `boards past the tack pulling tool comprising conveyor vchains and fingers connected therewith for engaging the notches in said flanges, and means engaging said members for positioning the boards laterally with respect to the tack pulling tool.

6. A tackv pulling machine having, in combination, a-ta'ck pulling tool,` means forfeeding the work 'past the tack pulling tool, and hold-down means comprising a plurality of bars extending transversely of the direction ofvfeed of the work,

and devices for moving the bars with the work while in engagement therewith during the tack pulling operation.

'7. A tack pulling machine having, in combination, a tack pulling tool, means for feeding the work past the tack pulling tool, and hold-down devices for engaging and traveling with the work during the Vtack pulling operation, said' devices comprising'a pair of spaced chains and a plurality of flexible, work-engagingbars arranged transversely of the direction of feed and carried by the chains.

8. A tack pulling machine having, in combination, a tack pulling tool, means for feedingthe work past thetack pulling tool, and hold-down devices for Y"engaging and moving with the work during the' tack pulling operation, said devices comprising a pairl of spaced endless conveyor chains withioppositely moving sections and workengaging members carried thereby and extending transversely ofthe direction of feed, and means for supporting the chains with the oppositely moving sections of eachA chain spaced apart and the tack pulling tool positioned between said sections.

9. A tack pulling machine comprising a rotary tack pulling tool having resilient members, a collector adjacent the tool tov receive withdrawn tacks, and depending means within the collector to prevent the escapeof the tacks therefrom.

' 10. A rotary tack pulling tool having a plurality of independent, resilient rtack engaging *mem-l,

bers provided with uninterrupted tack engaging l faces extending substantially the axial length of the tool.

ll. A rotary tack pulling tool having resilient tack engaging members comprising a plurality of long, thin tack engaging members, arranged parallel to theaxis of the tool and supported adjacent their ends with free intermediate tack engaging portions. d

12. A rotary tack pulling tool comprisinga shaft, a pair of supporting heads spaced on said Qshaft, and a plurality of tack `pulling wires stretched between the supporting` heads parallel `to the axis of the tool. l l l 13. A tack pulling tool comprising a shaft, a

pair of supporting heads spaced on the shaft, a plurality of tack pulling wires supported by the heads parallel to the axis of `the shaft, one of the heads being movable axially on the shaft to adjust the tension of the wires.

14. A tack pulling tool comprising a shaft,`sup

`porting heads spaced on the shaft, tack pulling wires stretched between the heads parallel to the axis of rotation, and means contacting the wires intermediate the heads to eliminate vibration of `the wires.

15. A tack pulling machine having, in combination, a rotary tack-pulling tool, means for feeding the work with the tacks partially ernbedded therein past the rotating tool, and means movable with the work and engaging the same for holding down the work adjacent the tool.

16. A tack pulling tool comprising a pair of spaced heads, tensioned wires extending between the heads, one of the heads being supported on a universalmounting to permit tilting, thereby to equalize the tension on the severalwires.

17. A rotary tack pulling tool having a plurality of tensioned, resilient tack pulling members. 18. A rotary tack pulling tool `havingthree l tack engaging tensioned wires.

19. A tack pulling tool comprising a shaft, supporting heads on the shaft,ltack pulling wires stretched between the heads, and members rotatably mounted on the shaft outside the head l and of greater diameter than the same. l

20. A tack pulling machine having, in combination, a rotary tack pulling tool, means for l feeding `pastthe tool boards to which skins or other material have been tacked, and independently rotatable means carried by the tool for spacing the boards therefrom.

2l.`A tack pulling machine having,` in combination, a tack pulling tool, means for feeding l the work past the tool, hold-down devices comprising a plurality of work-engaging members traveling with 'the work, and means for preventing contact of the work-engaging members with said tool,

22. A tack pulling machine having, in combinal tion, a rotating tack pulling tool, means for feeding the work past the rotating tool, hold-down devices comprising a plurality of work-engaging members traveling with the work, and independently rotatable means carried by the tack pulling tool for preventing contactof the work-engaging members with said tool.

23. A tack pulling machine having, in combination, a rotary tack pulling tool, means including conveyor chains for feeding the work past the tool, hold-down devices comprising a plurality of work-engaging members arranged transversely of the direction of feed, and means past the toolat substantially` the same rate of speed as the work. l

sitioned between said sections, a collector positioned adjacent the tool' between saidsections, anda conveyor comprising an endless belt running between said sections transversely to the direction of the workfeed for receiving and withdra'wing tacks from the .collector and discharging the tacks at one sideof the machine.

actuated by the conveyor chains to cause said work-engaging members to travel with the work 25. A ltack pulling machine `comprising a rol tary tack pulling tool having resilient members,

a collector adjacent the tool to receive the with--V drawn tacks, and a fireproof curtain within vthe collector to` prevent the escape of the tacks therefrom.

26. A tack pulling machine having, in combination, a rotating tack pulling tool and means for feeding past the tool boards to which the work is tacked with the headed portions of the tacks projecting from `the boards, said toolcomprising tack engaging members having a small radius of rotation `to cause the members to engage the `tacks with a substantial component of motion normal to the surface of the boards, therebyto withdraw the tacks approximately in the line"in l which they were driven.

2'?. A tack pulling machine comprising a rotary tack pulling tool, having resilient tack pulling membersand a collector adjacent the tool at the side thereof in the direction from which the work approaches and into which collector the with-drawn tacks are thrown by the resilient mem` bers and collected. l

28. A tack pullingmachine comprising a rotary tack pullingtool having resilient members beneath which the work is passed, a collector po-` sitioned above the work adjacent the tool and on the side thereof in the direction from which the` work approaches, and having an imperforate bottom and `a conveyor supported on the imperforate bottom of the collector to receive the tacks withdrawn from the work and thrown by the resilient members of `the tack `pulling tool and to discharge said tacks at a distant point. l

29. A rotary tack pulling tool comprising an elongated flexible.` elastic tack pulling member and means for supporting said member to per- `m1`t the same to engage the tacks in the work and to be extended thereby, and to withdraw and discharge the tacks by contraction of the elastic member,

ROGER L. GRIFFLN. NORMAN Y. MOORE, 

